1. Field of the Invention
In particular, the present invention describes an apparatus for performing arithmetic operations using a single control signal to manipulate multiple data elements. The present invention allows execution of shift operations on packed data types.
2. Description of Related Art
Today, most personal computer systems operate with one instruction to produce one result. Performance increases are achieved by increasing execution speed of instructions and the process or instruction complexity; known as Complex Instruction Set Computer (CISC). Such processors as the Intel 80286.TM. microprocessor, available from Intel Corp. of Santa Clara, Calif., belong to the CISC category of processor.
Previous computer system architecture has been optimized to take advantage of the CISC concept. Such systems typically have data buses thirty-two bits wide. However, applications targeted at computer supported cooperation (CSC--the integration of teleconferencing with mixed media data manipulation), 2D/3D graphics, image processing, video compression/decompression, recognition a lgorithms and audio manipulation increase the need for improved performance. But, increasing the execution speed and complexity of instructions is only one solution.
One common aspect of these applications is that they often manipulate large amounts of data where only a few bits are important. That is, data whose relevant bits are represented in much fewer bits than the size of the data bus. For example, processors execute many operations on eight bit and sixteen bit data (e.g., pixel color components in a video image) but have much wider data busses and registers. Thus, a processor having a thirty-two bit data bus and registers, and executing one of these algorithms, can waste up to seventy-five percent of its data processing, carrying and storage capacity because only the first eight bits of data are important.
As such, what is desired is a processor that increases performance by more efficiently using the difference between the number of bits required to represent the data to be manipulated and the actual data carrying and storage capacity of the processor.